The 25-year-old pharmacy intern whose death launched a murder investigation had staged his own suicide to look suspicious, police say.

Alvin Ahmed disappeared on July 16, after finishing his shift at a local Publix in Georgia. He had bought groceries for his mother, but they never made it home, and were found in his car along with his pharmacy coat.

Earlier, he had claimed to family and friends a group of young men had approached him, demanding information about his watch, his wage and his car.

Police now say all of these things, which would ordinarily be indicative of a more sinister death, were planned by Ahmed to make his suicide appear more suspicious.

Corporal Michele Pihera told the Atlanta Courier Journal investigating officers found evidence on Ahmed's phone showing he had planned to buy the groceries, and planned to leave his watch and switched-off phone at a nearby restaurant. He then planned to walk two miles to a lake, where he then took his own life.

The two-sentence note about his evening schedule was found in a 'reminders' app on his phone

His actions in the immediate lead-up to his death, and his comments about being accosted by the young men, led his family to believe their brother and son had been abducted.

But Pihera said a two-sentence reminder in an app on his phone had unravelled the recent university graduate's plan, and proven it was suicide.

'The phone data contained a note which indicated that Mr. Ahmed staged certain elements of the case to cast suspicion that he had been murdered,' Pihera said.

'There is no credible evidence that the case was a homicide.'

His older brother Kalvin Ahmed said the phone has not been found, but the app could be accessed via the internet.

Two days after Ahmed went missing, his body was pulled out of a lake in Gwinnett County. Medical examiners determined the body had died from a self-inflicted gunshot to the head.